BACKGROUND OF THE INVENTION
[0001] The present invention relates to devices such as surface acoustic wave (SAW) devices
which constitutes, for example, surface acoustic wave filters or surface acoustic
wave resonators, and devices which handle high frequency signals, and more particularly
to a small high-performance high-frequency module suitable for use in a radio communication
device such as a portable telephone set.
[0002] One example of the conventional packaged surface acoustic wave modules is shown in
Fig. 2a. A surface acoustic wave device 2 is die-bonded within a metal package 3 hermetically
sealable with a bond 4 and is connected to package terminals 12 by wire bonding at
16 through bonding pads 11.
[0003] Figs. 2b, 2c and 2d show hypothetical examples of a structure including a surface
acoustic wave device package shown in Fig. 2a die-bonded to a mother board, for example,
of a communication device. Generally, the impedance viewed from the input/output terminals
12 of the surface acoustic wave device is capacitative on the order of several pF
because of the existence of capacitance involving the finger electrodes of a transducer
1 which excites surface acoustic waves. Therefore, as shown in Fig. 2b, after a surface
acoustic wave device package 3 is die-bonded to a mother board 17, for example, of
a communication device terminal, external inductive matching circuits 18a, 18b are
connected to the input/output terminals to cancel the capacitance components, as shown
in Fig. 2c, 2d. Reference numeral 120 denotes input/output lines; 130, a ground potential
layer at which a surface to which the package 3 and high frequency device 2 are attached
is maintained via through holes 131. Fig. 2d shows the opposite side of the mother
board from the package 3 of Fig. 2b.
[0004] Such conventional SAW device shown in Fig. 2a is disclosed, for example, in "800-MHz
HIGH-PERFORMANCE SAW FILTER USING NEW RESONANT CONFIGURATION",
IEEE Transactions on Microwave Theory and Techniques, Vol. MTT-33, No. 6, June 1985, pp. 510-518, and "Miniature SAW Antenna Duplexer
for 800-MHz Portable Telephone Used in Cellular Radio Systems",
IEEE Transactions on Microwave Theory and Techniques, Vol. 36, No. 6, June 1988, pp. 1047-1056.
SUMMARY OF THE INVENTION
[0005] Conventionally, especially in a surface acoustic wave device, as shown in Fig. 2a,
a surface acoustic wave device chip 2 is attached so as to cover an upper surface
19 of a lower metal package portion 3b, and the device 2 and the input/output terminals
12 of the package are connected with bonding wires 16. For sealing purposes the metal
cap 3a is attached and fixed as by current welding. Generally, the surface acoustic
wave device has a large capacitative input/output impedance due to the existence of
inter-electrode capacitance inherent essentially to an interdigital transducer 1 (IDT)
which excites a surface acoustic wave. When such a surface acoustic wave device is
applied, for example, to a radio communication device, the input/output terminals
12 are provided so as to extend through the mother board 17 and soldered to the back
surface, as shown in Fig. 2b. In addition, in order to cancel the capacitative components
of the input/output impedances of the surface acoustic wave device, as shown in Figs.
2c and 2d, impedance matching is required using external matching circuits, for example,
of coil-like inductances 18a (Fig. 2c) and meander line-like inductances 18b (Fig.
2d).
[0006] The surface acoustic wave resonator used in a voltage-controlled oscillator, etc.,
influences the resonant frequency because the inductance, for example, of the bonding
wire is connected in series with the resonator according to the conventional die-bonding
techniques. When the length of the bonding wire changes, the resonant frequency also
changes. Therefore, in order to adjust a change in the resonant frequency due to the
use of a different length of the wire, external coils adjustable such as those shown
in Fig. 2c as separate tuning circuits are required to be used. The external matching
circuit is also used to adjust and absorb changes in the input/output impedances due
to different lengths of wires 16 for wire bonding as shown in Fig. 2a.
[0007] Active devices such as GaAs FETs also require an external matching circuit as is
the surface acoustic wave device.
[0008] Recently, in mobile communication represented by car telephone sets, a radio terminal
is miniaturized from a portable one to a pocketable one. A microminiaturized terminal
of a fountain pen type is expected to appear in the future. As such radio terminals
are miniaturized, very strict requirements are imposed on the devices used. Especially,
the surface acoustic wave devices are each small in itself, but they have many problems,
for example, involving provision of an external matching circuit and to be solved
in the course of miniaturization and non-adjustment of the entire terminal.
[0009] The surface acoustic wave devices are considered as most contributory to miniaturization.
However, they actually require external matching circuits, as shown in Figs. 2c and
2d. Thus, even if a surface acoustic wave device package 3 is miniaturized satisfactorily,
the merits deriving from such miniaturization are half reduced. Such problems also
exist in an external matching circuit for a semiconductor device such as a GaAs FET.
[0010] In order to solve these problems, it is an object of the present invention to provide
an attaching method of miniaturizing modules and reducing variations in the characteristic
of modules in fabrication and a high frequency module which builds a matching circuit
in the module and requires no adjustment.
[0011] In order to achieve the above object, according to one aspect of the present invention,
there is provided a high frequency module comprising a high frequency device in a
package, and either a distributed or a lumped constant circuit provided within the
package such that the distributed or lumped constant circuit performs impedance matching
or transformation for the high frequency device.
[0012] The high frequency device is either a surface acoustic wave device or a semiconductor
device and its circuit is formed on a flexible substrate made, for example, of polyimide.
[0013] As a specified structure, the package comprises a lower and an upper package portion,
the lower package portion having the high frequency device disposed therein. The substrate
is disposed over the high frequency device, the upper package portion being disposed
above the substrate. Input/output terminals for inputting/outputting signals to/from
the package and the circuit on the substrate are connected, and the circuit on the
substrate and the high frequency device are connected.
[0014] The high frequency device is preferably disposed at a ground potential and sealed
by the package.
[0015] The input/output terminals of the package, the leads on the substrate, the input/output
terminals of the high frequency devices may be connected directly or through bump
bonds, lead electrodes or conductive adhesives.
[0016] Formed on the substrate are lumped constant circuit of inductive devices, capacitative
devices or resistance devices. The inductive device is formed by photolithography
or with coils. Power supply lines for the high frequency devices may be disposed on
the substrate. If a plurality of high frequency devices is disposed within the package,
connection leads between the high frequency devices may be disposed on the substrate.
If the high frequency device is a surface acoustic wave device, the capacitor device
may be provided in a piezoelectric substrate of the surface acoustic wave device.
[0017] Electrical connections between surface acoustic wave device chips, between active
device chips including such as GaAs FETs, or between terminals of a package or a circuit
board and chips mounted thereon are made by circuits formed by a thin copper film
on a flexible substrate such as a film tape to thereby dispose a matching circuit
easily in the package.
[0018] At this time, the circuits on the substrate may be disposed floating within the package.
Therefore, the circuits are separated from the ground potential of the package to
thereby provide a preferable configuration as the circuit which handles high frequencies.
[0019] At this time, the circuit formed in the film tape includes matching circuits for
the surface acoustic wave devices and active devices or coils for tuning the surface
acoustic wave resonator.
[0020] The circuit pattern in the film tape is formed with thin copper films in a photolithographic
process similar to the manufacture of semiconductor ICs, so that very fine matching
circuits are realized without no variations. In addition, the connection electrodes
and matching circuits formed in the film tape can by themselves measure and evaluate
the high frequency characteristic of the respective circuits. Therefore, the result
of the evaluation can be used for design of the overall circuit to thereby render
the device optimal and eliminate up to problems with the packaging. Building the matching
circuits in the module achieves non-adjustment and miniaturization.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021]
Figs. 1a, 1b are a plan view and a cross-sectional view of an embodiment of the present
invention.
Fig. 2a illustrates the conventional technique, while Figs. 2b - 2d illustrate hypothetical
examples of a structure including the device shown in Fig. 2a.
Figs. 3a - 3c are respectively a cross-sectional view and plan views of an embodiment
of the present invention.
Figs. 4a, 4b are respectively a circuit diagram and a graph explaining the embodiment.
Fig. 5 is a circuit diagram indicative of an embodiment of the present invention.
Figs. 6a - 6e are a cross-sectional view, a plan view and fragmentary cross-sectional
views of embodiments of the present invention.
Fig. 7 is a cross-sectional view of an embodiment of the present invention.
Fig. 8 is a perspective view of an embodiment of the present invention.
Figs. 9a - 9d are perspective views of embodiments of the present inventions.
Figs. 10a, 10b are respectively a cross-sectional view and a plan view of an embodiment
of the present invention;
Figs. 11a, 11b are respectively perspective view of the Figs. 1 and 10 embodiments.
Fig. 12 is a perspective view of an embodiment of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0022] Embodiments of the present invention will be described in more detail with reference
to the drawings.
(Embodiment 1)
[0023] Fig. 1 shows an embodiment of the present invention. Figs. 1a and 1b are a plan view
and a cross-sectional view, respectively, of the embodiment.
[0024] A surface acoustic wave device chip 2 with a comb-type electrode 1 which generates
a surface acoustic wave is fixed on a piezoelectric substrate surface within a package
3 with a bond 4 and hermetically sealed with a cap 6. The main portion of the package
3 is made of alumina or ceramics. The surface acoustic wave device 2 is placed on
a ground potential layer 130.
[0025] Electrodes 8 are attached to a film tape 7, for example, of polyimide. Pads 11 of
the surface acoustic wave device 2 and input/output terminals 12 of the package are
connected by inner leads 9 and outer leads 10 through a film tape 7. Fig. 1a is a
plan view of the module without the cap 6 and film tape 7. As will be described later
in more detail, connection leads or matching circuits may be formed on the film tape
7. The surface acoustic wave device 2 which is a high frequency device is hermetically
sealed with the cap 6 made of a metal such as iron and with a metal wall 300 of the
package.
(Embodiment 2)
[0026] Figs. 10a and 10b show a surface acoustic wave device 2a and active devices 2b such
as ICs which are mounted on or die-bonded to the same package 3 or on a single substrate
(a mother board of a radio device), these devices 2a and 2b or these devices 2a, 2b
and the input/output terminals 12 of the package 3 being connected through a thin
copper circuit formed in a single- or multi-layered film tape 7. Reference numeral
200 denotes the main portion of a lower package portion made of alumina.
[0027] This embodiment illustrates the connection of the circuit formed in the film tape
7 and the devices 2a, 2b using bumps 13 such as solder, which is recently marked greatly.
[0028] Fig. 10b is a plan view of the module of Fig. 10a without the cap 6. The film tape
7 is provided with a matching circuit for a surface acoustic wave device, a matching
circuit for active devices and a power supply circuit formed in a thin copper film
pattern 100. Pads 14 are formed for connection with the devices 2a, 2b and the input/output
terminals 12 of the package 3.
[0029] Figs. 11a and 11b are respectively enlarged views of the film tapes 7 shown in Figs.
1 and 10. A single- or a multi-layered circuit pattern 100 is formed with a thin copper
film on a film 27, for example, made of polyimide to thereby form either a spiral
or a meander line-like inductance, a gap or a capacitance involving parallel plates,
a thin film or a thick film resistor and/or, as required, a chip part. Fig. 11a shows
a structure of a single film layer while Fig. 11b shows a two-layered film structure.
Connection between the opposite surfaces of the film or between circuit patterns on
the films are made through holes 28 formed in the films. Fig. 11 illustrates a coil
used for the matching circuit. In the embodiment of Fig. 11, the film 27 is about
50-500 µm thick, and the copper leads 100 are 5-200 µm thick and 5-200 µm broad.
(Embodiment 3)
[0030] Fig. 3 shows a die-bonding method by the present invention corresponding to the conventional
die-bonding method shown in Fig. 2. A surface acoustic wave device chip 2 is mounted
on a ground potential layer 130 in a ceramics-based flat package 36 such as that shown
in Fig. 3a. Formed on the film tape 7 as shown in Fig. 3b is a wiring conductor pattern
including matching circuits 18, package 36, and connection pads 14 for the device
2. The device 2 and the input/output terminals 12 of the package 36 are connected
by bumps 13 through the film tape 7. Simultaneously, impedance matching between an
external load and the devices is achieved.
[0031] Hermetical seal is achieved by attaching a metal cap 6, for example, made of iron,
to a protrusion 35 on the package by current welding or with a bond as in the conventional
manner. The cap 6, protrusion 35 are clamped to a ground potential. The surface acoustic
wave device 2, thus attached, has the matching circuit within the package, so that
no external matching circuits are required or greatly reduced in number. As shown
in Fig. 3c, the surface acoustic wave device of such construction can be directly
mounted on or die-bonded to a circuit substrate (mother board) 17 with a microstrip
line 313 having, for example, a characteristic impedance of 50 ohms.
[0032] In the present invention, the input/output terminals 12 used for attaching the package
3 are not required to extend through the mother board 17, as are the terminals of
the conventional device of Fig. 2b due to the package 3 being mounted or die-bonded,
and no external matching circuits are required. Thus, die-bonding of the embodiment
to the device is very easy. The mother board 17 is required to be processed only on
one circuit surface even when the package is attached over the mother board to thereby
improve the assembly efficiency.
[0033] More particularly, in the configuration of Figs. 2a - 2d, both the upper and lower
surfaces of the mother board are required to be used. The overall area of a 800 MHz-band
car telephone module additionally including the external matching circuits is, for
example, about 12 mm x 12 mm. In contrast, in the present invention of Fig. 3 only
one surface of the mother board is needed. In addition, in the car telephone sets,
the module is miniaturized to a size of about 2.5 mm x 2.5 mm which is the size of
the surface acoustic wave device chip.
[0034] Fig. 12 illustrates the actual matching circuit in a perspective view obtained by
further specifying the structure of Figs. 3a, 3b. The film tape 7 is disposed over
the surface acoustic wave device 2 die-bonded within the package 3 with a spacing
between the device 2 and film tape 7. The film tape 7 has the spiral or meander line-like
matching circuit 111 and connection leads for the device 2 and package input/output
terminals 12. The solid lines show leads on the front of the film tape 7 while the
broken lines show leads on the back surface of the tape 7.
(Embodiment 4)
[0035] Another embodiment will be described with respect to a specified circuit. Fig. 4a
shows an equivalent circuit of a voltage controlled oscillator (VCO) one or two of
which are necessarily used in a mobile radio terminal.
[0036] In the use of a resonator such as a conventional dielectric material resonator or
microstrip line as a VCO, the drawback is a great size. The use of a surface acoustic
wave resonator 41 serves to miniaturize the module. Generally, a VCO of surface acoustic
wave type resonator is narrow in variable frequency width and it is difficult to ensure
all the frequency band widths used in car telephone sets.
[0037] Such a drawback with the surface acoustic wave resonator is eliminated by the connection
of an inductance (coil) 42 of a relatively small value, for example, of 5 - 10 nH
in series or parallel with the surface acoustic wave resonator as shown in Fig. 4.
The impedance characteristic of the surface acoustic wave resonator has a value shown
by the solid line in Fig. 4b. Incorporation of such resonator into an oscillator results
in oscillation in a frequency region (between fr and fa) where the impedance is inductive.
Therefore, in order to broaden a variable frequency width, it is required to either
lower the resonant frequency fr or increase an anti-resonance frequency fa. For example,
as shown in Fig. 4a, series connection of an inductance 42 with the resonator causes
the impedance to change as shown by the broken lines in Fig. 4b. That is, fa-fr' is
broader than fa-fr. Thus, when the resonator is built in an oscillator, the variable
frequency width of the VCO is broadened. As an example, fr = 850 MHz, fa = 900 MHz
and fr' = 820 MHz.
[0038] The value of such an extension inductance must be determined with high accuracy.
[0039] The value of the inductance formed in a film tape, for example, of polyimide or glass
epoxy using a single- or multi-layered copper film, as described above, can be controlled
with high accuracy. As shown in Fig. 4a, the VCO also includes a power supply coil
43. The input/output terminals or the power source terminals are also required to
be connected to external devices. The formation of these elements in the film tape
as in Fig. 1 serves to reduce variations of inductances in the modules and to achieve
miniaturization.
[0040] Generally, a VCO requires capacitors 44, 46 and 47 for forming either a Colpits or
a Hartley oscillator and pass capacitors 45, 48 and 49. In the present embodiment,
part or all of these capacitors are realized by a gap structure or a dielectric multilayered
structure in a surface acoustic wave resonator chip. Generally, the piezoelectric
substrate used for a surface acoustic wave device has a very large relative dielectric
constant and a capacitance of several to tens of pF can be easily formed in the chip.
The simultaneous formation of these capacitances in the same process as that for forming
the surface acoustic wave resonator miniaturizes the overall circuitry and simplifies
the process. Such a technique is disclosed, for example, in Japanese Patent Publication
JP-A 63-132515 (U.S. Patent 4,803,449).
[0041] The VCO circuit of Fig. 4a uses many active devices such as a transistor 414 and
many resistors 410, 411, 412 and 413. Generally, the resistors can easily be formed
in an active device chip when the active device is formed as are many semiconductor
ICs.
[0042] A VCO of a single package structure, for example, shown in Fig. 10, is realized on
the basis of the study of the above description. In Fig. 10, the surface acoustic
wave resonator and part or all of capacitance components are formed in the surface
acoustic wave device chip 2a, and active devices such as transistors and part or all
of the resistance components are formed in the semiconductor device chip 2b. Connections
for the inductance (coil), input/output terminals and power supply terminals are formed
with a thin copper film formed on the film tape 7. By such construction, the surface
acoustic wave resonator 2a and semiconductor 2b are basically formed as respective
chips. By bonding the film tape with bumps 13 shown on top of the chip and input/output
terminals, a microminiaturized VCO which is miniaturized to the chip level is achieved.
Such VCO has an area slightly larger than the sum of the areas of a surface acoustic
wave resonator chip (about 2 mm x 2 mm) and a semiconductor device chip (about 1 mm
x 1 mm) and has a height substantially equal to that of the chip (about 0.4 mm). A
VCO very small in volume is achieved even when die-bonded to a flat package, as shown
in Fig. 1.
(Embodiment 5)
[0043] Fig. 5 shows an embodiment of another circuit producing larger effects by application
of the present invention. It also shows the front end unit of a radio receiver of
a car telephone set. A signal received through an antenna terminal (not shown) enters
a surface acoustic wave filter 51 of the first stage of the receiver, which provides
a signal in a reception band and attenuates unnecessary signals such as spurious ones.
Since generally the use of only the first stage filter is insufficient to attenuate
useless signals completely, a further surface acoustic wave filter 52 is used in the
next stage through a low noise amplifier 515 to ensure a required quantity of attenuation.
[0044] A direct current bias is required in each of the low noise amplifier and a mixer.
It is applied across a separate power supply terminal and ground.
[0045] The overall front end unit including the input/output terminals, surface acoustic
wave filter 52, low noise amplifier 515, and power supply terminals is shown in Fig.
5. A mixer is connected to the output of the front end unit of Fig. 5. The front end
unit can include a mixer.
[0046] The surface acoustic wave filter requires external inductances 53, 54, 56, 57, for
example, of 50 - 100 nH, to cancel inter-electrode capacitances of the transducer.
In the low noise amplifier, the semiconductor devices as the active ones and, as mentioned
above, the resistors can relatively easily formed as monolithic ones while capacitances
having a large value, for example, of 50 - 100 pH and matching inductances, for example,
of 10 - 20 nH are difficult to form as monolithic ones.
[0047] The present invention solves these problems. As in the VCO of Fig. 4, the matching
inductances for the surfaces acoustic wave filter and low noise amplifier are formed
with a thin copper film on the film tape, etc. Capacitors having an especially large
value are formed in the form of a gap capacitance in the surface acoustic wave filter
chip. The semiconductor devices and resistors are formed in the semiconductor chip.
Two surface acoustic wave filters and one semiconductor IC chip are connected to each
other by a thin copper film circuit formed on the film tape using bump techniques,
as shown in Fig. 1. When provided in the package, the input/output terminals and power
supply terminals for the package can be connected simultaneously through the film
tape. Therefore, the overall volume is substantially the same as the sum of the volumes
of three chips including two filter chips and one IC chip. According to this embodiment,
great miniaturization is achieved compared to the conventional techniques including
the steps of providing a surface acoustic wave filter hermetically sealed within a
can type package on a mother board of a radio device, using external matching circuits
in the input/output units, and forming a low noise amplifier in a similar circuit
type. Even if there is a mixer, etc., at the next stage of the Fig. 5 module, larger
scale integration including the formation of a mixer can be achieved using a similar
technique.
[0048] That is, the present embodiment can be constituted as one package device, as shown
in Fig. 10. The film tape 7 advantageously has a small parasitic capacitance because
it is isolated from each of the upper and lower ground level layers through a space.
[0049] The present invention has been described above using the specified circuit of the
radio device. While in the various embodiments the connection between the surface
acoustic wave device and the semiconductor chips and the connection between the devices,
chips and the terminals through the film tapes using bump techniques have been illustrated
on the basis of the module of Fig. 1, the connection using bump techniques is not
necessarily required.
(Embodiment 6)
[0050] As an example of simpler connection, a chip 2 and a film tape 7 can be connected
by bonding at 62 as in the conventional techniques, as shown in Figs. 6a and 6b. In
addition, many connection methods could be considered. Various connections between
the film tape and, for example, the package input/output terminals could be considered.
[0051] Several examples are shown in Figs. 6c, 6d and 6e. Fig. 6c shows a technique of connecting
the package and a bent film tape 7 with a conductive adhesive 625. Fig. 6d shows a
technique of forming a post-like conductor 627 on the package and connecting the conductor
and the film tape. Fig. 6e shows the technique of forming a dummy chip 629 having
substantially the same height as a surface acoustic wave device or a semiconductor
IC chip so as to cover the package terminals, and connecting the device or chips and
the dummy chip through a through hole 628 in the dummy chip 629. As described above,
the present invention uses a substrate of a flexible material, so that the degree
of freedom of providing devices is very high.
(Embodiment 7)
[0052] The above embodiments have the structures in which the surface acoustic wave device,
semiconductor IC chips are connected through the circuitry formed on the film tape
or the like, and the resulting assembly is attached to the flat package or the like.
The flat package is the one which has no terminals extending through the mother board
and on which the devices or the like can be provided. When miniaturization of a radio
device terminal is strictly required, temporary provision of the devices in the package,
and provision of the package on the mother board of the radio device or the like would
increase a useless space, and the number of steps of die-bonding the devices, which
is not necessarily an advantageous method.
[0053] Fig. 7 shows one example of a die-bonding method of solving the above problems. A
surface acoustic wave device 2 and semiconductor ICs are directly die-bonded to the
mother board 17 of a radio device and connection is made through the film tape 7 between
the devices including circuits on the mother board 17 or between the input/output
terminals 72 and the devices. In such die-bonding, the overall area of the mother
board occupied by the devices is substantially equal to that by the chips, so that
the devices are die-bonded in a very small area. Fig. 7 further shows the overall
module covered with a mold 73 such as silicone rubber or resist in consideration of
the passivation of the devices.
(Embodiment 8)
[0054] Fig. 8 shows another embodiment solving similar problems. This embodiment is the
same as the above embodiments in that the surface acoustic wave devices or semiconductor
ICs 82, 83, 84 are connected through a film tape, but differs in that the film tape
has a function similar to that of the mother board of the radio device to thereby
greatly reduce the volume occupied by the devices. A very multi-layered film tape
circuit is die-bonded in the radio device terminal by the use of the flexibility of
the film tape 7. Passivation may be performed with a molding material such as a resin
as in Fig. 7.
(Embodiment 9)
[0055] In the above embodiments, we proposed a die-bonding method of connecting the surface
acoustic wave devices and semiconductor ICs through the thin copper film circuit formed
on the film tape. Thus, substantial miniaturization is achieved compared to the conventional
die-bonding techniques. A matching circuit of a multi-layered structure is formable
with a thin copper film on the film tape or the like, as shown in Fig. 11.
[0056] In addition to the matching circuit, lumped constant inductances 92, 97 of thin copper
or gold coils 92, 97 as shown in Figs. 9a, 9b; a chip capacitor 99 of a laminated
dielectric film of Fig. 9c; and circuit elements such as a thick or thin resistor
911 of Fig. 9d are formable. The thick or thin film resistors are formed by the printing
of a resistor material. While the above embodiments are described using the film tapes,
a similar die-bonding method is achieved if a fine circuit pattern is formable and
a substrate flexible to some degree is used. The present invention includes those
packaging methods. In the above description, like elements are identified with like
reference numerals and characters.
[0057] In mobile radio communication devices, the surface acoustic wave devices are said
to most contributory to miniaturization, but have many problems to be solved in terms
of performance and die-bonding. Thus, the surface acoustic wave devices are not used
very prevalently. Especially, in the prior art, the hermetically sealed devices are
conventionally die-bonded to the mother board of a radio device and external matching
inductances are provided, so that the total occupied volume is not greatly reduced,
and the merits of miniaturizing the surface acoustic wave devices are half reduced.
The present invention solves these problems. According to the present invention, a
surface acoustic wave device is provided which is miniaturized to a chip level by
the formation of a required matching circuit on a multi-layered film tape of polyimide
or the like, and the connection of the surface acoustic wave device chip and the film
tape using bump techniques. The present invention produces large advantageous effects
not only in the surface acoustic wave devices, but also in semiconductor ICs or for
the combination of the wave devices and the ICs.
1. A high frequency module comprising a high frequency device (2) in a package (3), and
either a distributed or a lumped constant circuit (92, 97) within the package such
that the distributed or lumped constant circuit performs impedance matching or transformation
for the high frequency device.
2. A high frequency module according to Claim 1, wherein the high frequency device (2)
is either a surface acoustic wave device (2a) or a semiconductor device (2b) and wherein
said distributed or lumped constant circuit is formed on a flexible substrate (7)
of the surface acoustic wave device on the semiconductor device.
3. A high frequency module according to Claim 2, wherein said package comprises a lower
and an upper package portion (200, 6), said lower package portion (200) having said
high frequency device (2) disposed therein, said substrate (7) being disposed over
said high frequency device, said upper package portion (6) being disposed above said
substrate, input/output terminals (12) for inputting/outputting signals to/from the
package (3) and said substrate being connected, the circuit (92, 97) on said substrate
and input/output terminals (11) of said high frequency device being connected.
4. A high frequency module according to Claim 3, wherein said high frequency module is
disposed at a ground potential (130) and sealed by said package (3).
5. A high frequency module according to Claim 3, wherein input/output terminals (12)
of the package and the circuit (92, 97) on the substrate are connected through a first
conductor, and the input/output terminals (11) of the high frequency device (2) and
the circuit on the substrate are connected through a second conductor (9).
6. A high frequency module according to Claim 3, wherein a wiring conductor pattern on
the substrate (7) are connected to the input/output (12) of the package, the input/output
terminals (14) of the high frequency device (2) being connected to the wiring conductor
pattern on the substrate through a bump (13).
7. A high frequency module according to Claim 3, wherein the high frequency device (2)
is disposed on a ground potential member (130) of the lower package portion (200),
and wherein the upper package portion (6) is at a ground potential.
8. A high frequency module according to Claim 3, wherein the input/output terminals (12)
of the package (36) are disposed at the lower package portion (200), wherein the substrate
(7) is disposed bent over the high frequency device (2), and wherein the input/output
terminals of the package (3) and the high frequency device are connected by a wiring
conductor pattern on the substrate.
9. A high frequency module according to Claim 2, wherein the package (3) comprises a
lower package portion (200) and an upper package portion (6) joined to the lower package
portion, the high frequency device being disposed on the lower package portion, the
substrate (7) being disposed on the high frequency device (2), a wiring conductor
pattern on the substrate being directly connected to input/output terminals of the
package disposed in the lower package portion, the input/output terminals (12) of
the high frequency device being connected to the substrate through a conductive material
(13).
10. A high frequency module according to Claim 9, wherein the substrate (7) is bent and
disposed such that the wiring conductor pattern on the substrate contact the input/output
terminals of the lower package portion.
11. A high frequency module according to Claim 9, wherein the input/output terminals (12)
of the lower package portion (200) are connected to post-like conductors such that
the post-like conductor (627) contact the wiring conductor pattern on the substrate.
12. A high frequency module according to Claim 9, wherein the input/output terminals (12)
of the lower package portion (622) are connected to a dummy chip (629) substantially
flush with the high frequency device (2), and wherein a conductor on a surface of
the dummy chip connected to the input/output terminals contacts the wiring conductor
pattern on the substrate.
13. A high frequency module according to Claim 2, wherein the package (3) comprises the
substrate (17) on which the high frequency device is disposed and an isolating material
deposited on the substrate (17).
14. A high frequency module according to Claim 2, comprising an inductive device (92)
formed on the substrate (7) by photolithography.
15. A high frequency module according to Claim 2, wherein the package encloses (3) the
surface acoustic wave device (2a) and the semiconductor device (2b), and comprising
matching circuits (111) for the surface acoustic wave device (2a) and the semiconductor
device (2b) formed on the substrate.
16. A high frequency module according to Claim 2, wherein the package encloses a plurality
of high frequency devices connected by a wiring conductor pattern on the substrate.
17. A high frequency module according to Claim 2, wherein the high frequency device (2)
is a surface acoustic wave device (2a), and comprising a capacitor (99) on a piezoelectric
substrate (7) of the surface acoustic wave device.